300SD Trans. Slipping

I have developed a problem with the transmission on my 1982 300 SD. Whenever the car is in first gear, it slips, meaning it momentarily feels as though it goes into nuetral with no acceleration.
Two weeks ago the car was not shifting at all, so I changed the trans fluid and the filter, and then it started to work great.
Last week, however, this started. Once it gets into 2nd gear, it works fine. It is VERY annoying because I cannot accelerate from a stop sign or a traffic light. The 2-3 Shift also feels softer than before. Can this be the beginning of the B2 Problem, or can this be caused by some mis-adjustment. The vacuum lines all tested to be good.
Any help is appreciated.
Thank You
Tony Konstantinidis

[Benzmac]

I think it may be time for a reman unit. The only way to know is to take it to the mechanic.

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Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

[Aaron]

I think a reman unit would be the best bet as well. There is a pressure modulation valve that can be adjusted on the tranny, but that generally is for setting gearchanges. For example, it can be set so that the tires will "bark" at each shift, or it can be set for smoother transition, but that generally leads to slipping between gears. Might as well give it a try. Couldn't hurt.


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Rgds,
Aaron Greenberg
MB technician
'67 250SE Cabriolet
'77 450SL
'79 6.9
'79 6.9
'80 300SD
'81 240D
'85 380SE
'89 420SEL
'93 300E 2.8

[Robert W. Roe]

My '84 was about an inch or so low on ATF as read on the dipstick. I checked the level with the engine running, as the owners manual suggests. Added maybe 1/3 quart. It had been taking up to 5 sec to shift from P to D; now this is reduced to about 2 sec.

Unfortunately, when I went to check the level of the ATF after adding some, the whole dipstick was streaked with ATF, so I couldn't top it accurately. Did I add about the right amount, too much or too little? Does anyone know if I can check my ATF level with the engine either cool and/or shut off?
Thanks in advance,

Robert W. Roe
1984 300SD 165K miles


[This message has been edited by Robert W. Roe (edited 08-18-1999).]

These transmissions had a problem with the B2 piston. The original piston will break into pieces. It's easy to check. With the car on a lift remove the B2 piston cover on the right side of the trans...if it's broken there will be a spring and several pieces of aluminum visible. If it's okay, there will be no spring pressure on the cover(since the spring is captive when the assembly is in one piece). When they fail 1st and 2nd gear slip. There is an updated part to replace the original when it fails.
Regards,
Randy D.

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W.R.Durrance
ASE Master Tech
Mercedes Tech 19 Years

[Robert W. Roe]

I was able to get my transmission fluid up to about the right level; had to add about a half quart. Delay shifting from P to R or D is now similar to other MB's I've owned, about 1.4 sec or so.

Here's what's going on: when the car is cold, acceleration is sluggish up to about 2500 rpm, then I feel a distinct turbo boost and she pulls strongly up to 4000-4600 rpm (if I floor it) and upshifts pretty cleanly (well, for an MB tranny .) Is there a safety mechanism built-in somewhere to keep the turbo from running until the oil is warm?

Does it sound like the tranny is ok but the engine may need a "tune-up?" I'm wondering what to expect if I have a good mechanic check it out. Valve adjustment, filters, injectors, timing chain, or algae in the tank are all things I'm pondering. I want to improve low rpm torque without hurting fuel economy.

Also, where exactly is the "banjo bolt?" I'm not sure what it's called technically. What do I need to remove to access it? In other words, is cleaning it a fairly easy job for a careful but novice do-it-yourselfer? Or am I best not tackling it due to the risk of damaging something expensive? I have tools, a set of car ramps and an Impco book to use for parts identification, and some free time, but not much. Wondering if the 126 CD-ROM manuals are out yet.

Robert W. Roe
84 300SD 165,240 mi.

[This message has been edited by Robert W. Roe (edited 08-22-1999).]